Fuel injection pump for internalcombustion engines



April 10, 1951 K. BROOK ET AL FUEL INJECTION PUMP FOR INTERNAL-COMBUSTION ENGINES Filed Feb. 20, 1948 Patented Apr. 10, 1951 FUEL INJECTION PUMP FOR INTERNAL- COMBUSTION ENGINES Kenneth Brook, Eastcote, and Fraser Mackie Evans, London, England, assignors to C. A. V. Limited, London, England Application February 20, 1948, Serial No. 9,655 In Great Britain February 22, 1947 4 Claims.

This invention relates to fuel injection pumps of the reciprocatory type for internal combustion engines, in which reciprocatory motion is imparted to the plunger in one direction by a rotary cam and in the other direction by a spring. Ordinarily the motion is transmitted from the cam to the plunger by an intermediate thrust piece which is axially adjustable, the adjustability being required to bring the plunger into proper relation with parts in the pump cylinder,

I or to bring difierent plungers in a multi-cylinder pump into proper phase relationship.

In the specification of our co-pending application Serial No. 6156 we have described an invention which has for its object to provide an improved thrust piece enabling the desired adjustment to be effected in a simple and convenient manner. The said invention comprises a thrust piece formed by a pair of axially adjustable parts adapted to accommodate between them an adjusting shim.

In the further development of the said invention we have found that in the event of sticking of the pump plunger in its barrel, it is possible for the parts of the thrust piece to become separated with consequent risk of displacement of the shim, and to obviate this condition we have devised an improvement which forms the subject of the present invention.

The improvement comprises a thrust piece as claimed in our previous specification above mentioned, and having combined with it means for obviating risk of displacement of the shim.

In the accompanying drawings:

Figure 1 is an elevation in section of a part of the driving mechanism of a fuel injection pump for internal combustion engines constructed in accordance with the invention;

Figure 2 is a similar view showing a modified construction;

Figure 3 is a similar view showing a further modification;

Figure 4 is a horizontal section of the modifiprising a pair of parts 4 and 5, the former, slidable in a bore 6, and the parts being separated by a shim l permitting axial adjustment of the said parts. According to the present invention the shim l is accommodated in a recess 8 formed in the end of the part 4 adjacent to the shim, and a spring ring 9 is let into the said recess. The ring abuts on one side of the shim, and by its grip on the sides of the recess, holds the shim in position in the event of separation of the two parts of the thrust piece.

In an alternative mode of carrying the invention into efiect as illustrated in Figure 2, the shim 1 is located in a recess 8 in the part 4 as in the previously described example, and between the two parts 4 and 5 of the thrust piece there is placed a helical compression spring II] which at one end bears on the shim. The spring is such that in the event of separation of the parts of the thrust piece it can extend sufiiciently to hold the shim in position.

In another mode of carrying the invention into effect as illustrated in Figures 3 and 4, the shim I is located in a recess 8 in the part 4 as in the previously described examples, and the two parts 4 and 5 of the thrust piece are interconnected by a spring ring I I lying within a recess in the part 5. One end of the spring ring is extended radially outwardly at l2 through a hole 13 in the side of the part 5 and a coaxial hole I4 in the side of the part 4. The parts 4 and 5 are thus anchored together.

By any of the devices above described, risk of accidental dislodgement of the shim can be eliminated in a very simple and reliable manner.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

l. A reciprocatory pump of the kind specified, having in combination at least one plunger, a spring acting on said plunger, a cam for moving said plunger against the action of said spring, a thrust piece through the medium of which said cam acts on said plunger, and which is composed of a pair of axially adjustable parts, at least one adjusting shim arranged between said axially adjustable parts, and spring means carried by said thrust piece for obviating risk of displacement of said shim.

2. A reciprocatory pump as claimed in claim 1,

2,548,342 3 4 in which said spring means consists of a spring REFERENCES CITED ring engaging one of said axially adjustable parts The following references are of record in the and bearing on said shim. file of this patent:

3. A reciprocatory pump as claimed in claim 1,

in which said spring means consists of a helical 5 UNITED STATES PATENTS compression spring located between said axially N b Name t adjustable parts and bearing on said shim. 2,138,359 Edwards Jan 30 19 0 4. A reciprocatory pump as claimed in claim 1, 2,225,019 m 7, 9 0 in which said spring means consists of a spring ring interconnecting said axially adjustable parts. 10 FOREIGN PATENTS Number Country Date KENNETH BROOK. 5813878 Great Britain 1946 FRASER MACKIE EVANS. 349,459 France 1939 

